The cerebellar vermis is the narrow, unpaired strip of tissue along the midline of the cerebellum that joins its two hemispheres, in the posterior cranial fossa at the back of the skull. Vermis is Latin for “worm”. [1][2]
Not a separate shape in this atlas; lit: the part that holds it. Lit: the whole cerebellum. The vermis is the middle strip of the cerebellum, and the BodyParts3D model draws the cerebellum as one shape with no vermis border, so nothing is drawn at a guessed point. [2][1]
The 3D brain needs JavaScript. The text below still says where the cerebellar vermis is and what it does.
Slice
Opens cut by a side (sagittal) slice through the cerebellum, which holds the cerebellar vermis. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Lit here: the cerebellum, the part that holds the cerebellar vermis — see it on its own page.
It is the unpaired, median portion of the cerebellum that connects the two hemispheres, in the medial, cortico-nuclear zone. [1]
The primary fissure crosses the vermis and curves round to the upper surface of the cerebellum, dividing it into anterior and posterior lobes. [1]
It helps form the roof of the fourth ventricle: the lower part of that roof is formed by the inferior medullary velum and the cerebellar vermis. [3]
The fastigial nucleus, the deep cerebellar nucleus nearest the midline, lies at the front end of the superior vermis, just over the roof of the fourth ventricle. [4]
What it does
It is associated with bodily posture and locomotion; it belongs to the spinocerebellum and receives body-sense input from the head and the parts of the body near the trunk through ascending spinal pathways. [1]
Purkinje cells of the vermis project to the fastigial nucleus, controlling the axial (trunk) and proximal (near-the-trunk limb) muscles used in carrying out limb movements. [1]
Through the vestibulospinal and reticulospinal tracts, the fastigial nucleus’s outputs are involved in regulating balance and posture. [4]
Connections
The fastigial nucleus it projects to sends fibres on to the vestibular nuclei, the reticular formation and the ventral lateral nucleus of the thalamus, leaving through the inferior cerebellar peduncle. [4]
Inside it
Nine lobules, top to bottom: lingula, central lobule, culmen, clivus, folium of the vermis, tuber, pyramid, uvula and nodule. The culmen is the largest, the uvula the second largest. [1]
The lobules vary between people in size, shape and number of folia, and are often hard to make out in anatomy classes. [1]
It forms first: the vermis is fully foliated by 4 months of prenatal development, while the hemispheres lag behind by 30–60 days. [1]
The model has no shape for the cerebellar vermis itself, so it is not measured here. The cerebellum that holds it measures about 56 mm front to back, 53 mm top to bottom and 106 mm side to side on this model (the box it fits in, not its volume). [5]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.